I have trouble on the IBC totes on the initial cleaning!
Tire shop guy gave me one that held the chemical they use to make foam-filled tractor tires. So not worth it. Never got it clean.
I like the ones with oil products in them. I leave them in the hot sun, then drain to my oil pan. Rinse the bottom 4" twice with a lot of Dawn dish soap. Then fill it overnight with some Dawn in the water. Those are always clean when I drain them the next day.
